We show that the total gluon helicity ΔG in a polarized nucleon can be calculated on a Euclidean lattice through a universality class of QCD operators that describe the helicity or polarization of the onshell gluon radiation. We in particular find some operators whose matrix elements in a nucleon of momentum Pz are directly related to ΔG with only power-law (1/Pz)n(n≥2) corrections.
@article{arxiv.1310.4263,
title = {Gluon Helicity Delta G from a Universality Class of Operators on a Lattice},
author = {Yoshitaka Hatta and Xiangdong Ji and Yong Zhao},
journal= {arXiv preprint arXiv:1310.4263},
year = {2014}
}